Bubble Shaped Membrane and Use of Such Membrane in a Device

ABSTRACT

The invention relates to a membrane ( 17 ) completely covering an opening ( 13 ) giving access to a space in a device which membrane ( 17 ) is made of an elastic material penetrable by a needle, the membrane ( 17 ) is fastened around the opening ( 13 ) and the membrane ( 17 ) protrudes from the opening ( 13 ) and forms an air filled volume in front of the opening ( 13 ) which air filled volume can be reduced in size when a pressure is put on the membrane ( 17 ) from the outside, the inner surfaces of the membrane ( 17 ) define a passage ( 17   a ) at the first closed end of the membrane ( 17 ) through which a needle ( 19 ) can pass and the second end of the membrane ( 17 ) is adapted to attach the membrane ( 17 ) to a holding part ( 61 ). The walls of the membrane ( 17 ) have a thickness and shape of the chosen membrane material making it possible, to maintain the protruding shape in a use position without the outer surfaces of the membrane ( 17 ) are supported with walls of rigid material. Also the invention relates to a device in which the membrane is used, and a kit where this device is combined with a corresponding unit.

THE TECHNICAL FIELD

The invention relates to a soft membrane which is used when it isnecessary to join units while keeping fluid paths of the units understerile conditions. Such membranes are often used when medication ornutrients are transferred sub- or transcutaneously to a patient.Especially when a continuously flow of medication e.g. insulin ornutrients are supplied to a patient it is necessary to keep access ofmicro organisms under control.

PRIOR ART

WO 2007/071255 (FIG. 19) describes the use of a soft membrane of similartype as the invention. FIG. 19 in this patent application shows anembodiment of a fluid tight connection between a reservoir and aninjection part. This device comprises a delivery part where of only areservoir 4 is shown in FIG. 19. The device is constructed of areservoir where the outlet is covered by a bubble shaped deformablemembrane 26; this membrane prevents that micro organisms access thereservoir when the delivery part is not joined to the injection part 1.The membrane does not only cover the tip of the connector needle 6 butcovers or surrounds a larger part of the connector needle 6. The inletof the injection part 1 is also covered by a deformable bubble shapedmembrane 27 and the connector needle 6 is here fastened to the injectionpart 1 but the connector needle 6 could also be fastened to the deliverypart 3, 4.

It is difficult to control the deformation of these known membranes andalso the closed spaced inside the membrane might be wetted with thefluid which is being transferred to or from the device through themembrane.

THE INVENTION

The object of the invention is to provide a membrane completely coveringan opening giving access to a space in a device. The membrane is made ofan elastic material which can be penetrated by a needle, the membrane isfastened around the opening and the membrane protrudes from the openingand forms an air filled volume in front of the opening which air filledvolume can be reduced in size when a pressure is put on the membranefrom the outside, the inner surfaces of the membrane define a passagethrough which a needle can pass and at least a part of this passage isdefined by having a reduced cross-section of air-filled volume. Thereduced cross-section of the air-filled volume provides this part of themembrane with a certain rigidity which makes it maintain the shape it isprovided with before being subjected to an external pressure. That thematerial is elastic means that it can be deformed when influenced byexternal forces and after the forces which deformed the material havebeen removed the material will return to the original shape. That themembrane is fastened around the opening does not mean it necessarily hasa shape similar or corresponding to the opening although this might bethe case, it only means that the contact between the membrane and thedevice provides a fluid tight closure for the whole opening. The “airfilled volume” can be filled with any form of gas. Normally it will begas used for sterilization mixed with air, and normally the volume willbe filled at least mainly with air.

More specifically the invention relates to a membrane completelycovering an opening giving access to a space in a device which membraneis made of an elastic material penetrable by a needle, the membrane isfastened around the opening and the membrane protrudes from the openingand forms an air filled volume in front of the opening which air filledvolume can be reduced in size when a pressure is put on the membranefrom the outside, the inner surfaces of the membrane define a passage atthe first closed end of the membrane through which a needle can pass andthe second end of the membrane is adapted to attach the membrane to aholding part. The membrane is characterized in that the walls of themembrane have a thickness and shape of the chosen membrane materialmaking it possible to maintain the protruding shape in a use positionwithout the outer surfaces of the membrane being supported with walls ofrigid material.

The membrane can be made e.g. of silicone or a flexible thermoplasticmaterial.

According to one embodiment the membrane is supported with walls of arigid material on the inner surfaces e.g. in the form of a penetratingneedle.

That the membrane is in a use position means that the membrane ismounted on or with the device with which it is supposed to be used e.g.as suggested in the present text the membrane is mounted in an infusiondevice where it can protect an inlet for medication.

According to one embodiment the second end of the membrane has aninternal opening fitting around the outer contour of a protruding parton the holding part and that the membrane is fastened to the holdingpart by interference fit.

According to an embodiment of the membrane the cross-section of theair-filled volume in the passage is smaller than 2·[max cross-section ofthe opening from the device to the membrane].

According to an embodiment of the membrane the passage is formed byincreasing the thickness of the membrane compared to parts of themembrane which does not form parts of the passage.

According to an embodiment of the membrane the space in the device issterile. The device including the air filled volume is normallysterilized before use of the device and kept sterile during use of thedevice.

According to an embodiment of the membrane the properties of thematerial forming the membrane varies making it possible to predict howthe air filled volume is reduced when subjected to an external pressurei.e. how the membrane is folded. The properties might e.g. be thethickness or the flexibility of the material.

According to an embodiment of the membrane the opening is provided atthe end of a needle fastened unreleasably to the device providing afluid path into the device and the needle is placed in the air filledvolume and during periods where no pressure is put on the membrane thepart of the needle extending into the air filled volume is completelysurrounded by air. The needle will during periods where pressure is puton the membrane extend through the membrane and protrude from the outersurface of the membrane. Further the needle is a blunt needle or apointy needle. A blunt needle is not able to cut through the membrane byitself but has to be presented with some kind of opening, a pointyneedle can by itself cut through the membrane and it would not benecessary to provide the membrane with an opening.

According to an embodiment of the membrane the membrane can bepenetrated by a blunt or a pointy needle.

According to an embodiment of the membrane a part of the membranepositioned closest to the device to which the membrane is fastened isthinner and more compliant and the material of the membrane positionedfurthest away from the device is thicker and more rigid. “The part ofthe material positioned closest to the device” does not refer to aparticular fraction of the material but more to a band of materialextending along the full circumference of the material closest to theopening.

According to an embodiment of the membrane the material of the membranepositioned closest to the device has the thickness b₁ and has the formof a hollow truncated cone or a cylinder and the material positionedfurthest away from the device has a thickness b₂ and has the form of ahollow cylinder which is closed at the end opposite the device, andb₂>b₁.

According to an embodiment of the membrane a part of the membranepositioned between the material closest to the device having thethickness b₁ and the material positioned furthest away from the devicehaving a thickness b₂, has a thickness varying from b₁ to b₂, accordingto one embodiment b₂≧1.5·b₁.

According to another embodiment of the membrane b₂<b₁ and the distancebetween the rigid material supporting the inner surfaces of the membranewhich could e.g. be a connector needle and the inner surfaces of themembrane is less than 0.5 mm.

According to second aspect the invention comprises a kit comprising adevice comprising a membrane according to any of the claims and areservoir unit adapted to be joined to the device assuring a steriletransfer of fluid between the device and the joined reservoir unit.

According to a third aspect the invention comprises a device comprisinga membrane according to any of the claims relating to a membrane, andcomprising a base part which base part comprise a surface plate andfastening means which fasten the base part to a subject, a fluid path isattached to the base part and the fluid path has at least to openings aninlet and an outlet for fluid, where one opening is protected by themembrane and the second opening is during use connected to a penetratingpart which can transfer fluid to and from the subject in which it isinserted.

Embodiments of the invention will now be described with reference to thefigures in which:

FIG. 1 shows a cut-through view of a membrane according to theinvention.

FIG. 2A, B and C show an embodiment of a connection part including theinternal parts.

FIG. 2D and E show an enlargement of a cannula part which can be usedtogether with the connection part.

FIG. 3A-C shows several embodiments of sealings in the form of a bubbleshaped membranes which can be used in connection with the invention.

FIG. 4A shows an embodiment of a device where the delivery part isseparated from the base part (seen from below).

FIG. 4B shows an embodiment of a device where the delivery part isseparated from the base part (seen from above).

FIG. 4C shows the same embodiment as FIG. 4A and 4B seen from anotherangle.

FIG. 5 shows an enlargement of a second embodiment of a membraneaccording to the invention

FIG. 1 shows an enlargement of an embodiment of a membrane 17 accordingto the invention. This bubble membrane 17 completely surrounds the partof the connector needle 19 which protrudes from the surface of theholding part 61 in which the connector needle 19 is embedded. Accordingto this embodiment the connector needle 19 does not touch the bubblemembrane 17 when no pressure is put on the membrane 17 i.e. theconnector needle 19 is completely surrounded by air which makes itpossible to gas sterilize the connector needle 19; this is the state inwhich the membrane is shown in the figure. At the proximal end of themembrane 17 in a first area, the membrane 17 provides a passage 17 ainside the membrane 17 having a reduced cross-section compared to amiddle area of the membrane 17 surrounding a middle section of theneedle 19. The passage 17 a is defined by the inner surfaces of thewalls of the membrane 17. The tip of the connector needle 19 issurrounded of quite thick walls constituted of the membrane forming asmall air filled room around the tip of the connector needle 19 andproviding the membrane material with a certain rigidity, while a middlepart of the membrane closer to but free of the holding part has walls ofapproximately half this thickness providing flexibility of the walls,this has the result that when pressure is put on the membrane the thickwalled part does not change shape, in stead the part of the membranehaving reduced wall thickness i.e. the part closest to the holding partwill give in, fold inward or outward, while the thick walled part ispressed toward the holding part 61. The membrane 17 further is providedwith an open end 17 b closest to the holding part 61; this open end 17 bof the elastic membrane material fits around a protruding part 61 a ofthe holding part 61. Due to friction between the inner surfaces of theopen 17 b end of the membrane 17 and the protruding part 61 a, themembrane 17 stay put in the desired position i.e. the membrane is keptin position as a result of the interference fit.

Generally a membrane 17 according to the present invention surrounds aneedle 19 and comprises three separate and identifiable areas whichareas can be defined relative to the needle 19:

a first area surrounds the tip of the needle 19, this area comprisesrelatively thick walls and small fluid volume around the needle 19,

a second area surrounds a middle portion of the needle 19 havingrelatively thin walls and/or walls with folding features e.g. portionswith very thin wall thickness or in another way prepared to ease lengthreduction of the membrane 17, and

a third area which area is provided with means for or adapted to attachthe membrane 17 to the holding parts 61 e.g. by fitting around aprotruding part 61 a of the holding part 61.

Also a membrane 17 according to the present invention need not beabutted to or supported by surrounding walls of rigid material, thismeans that the membrane 17 is free to deform e.g. by bulking outwards inone or more bulk(s) depending on the folding features of the second areawhen pressure is put on the membrane 17. Without rigid materialsurrounding the sides of the membrane 17, also the sides of the membrane17—and not only the end—can also be penetrated by e.g. a syringe therebyadding fluid to the inside of the membrane 17 i.e. there is free accessto at least part of the side area of the membrane 17.

The first area comprises the material of the membrane 17 which ispositioned furthest away from the device i.e. the closed end piece whichhas to be penetrated by a needle 19 in order to form contact with e.g. areservoir part placed outside the bubble shaped membrane 17. Themembrane material in this first area is formed as a cavity having sidesplaced along the needle, a closed end to be penetrated by the needle 19,and an open end through which the needle 19 enters. The sides have aminimum material thickness b₂ which is large enough to make the firstarea non-deformable but the material thickness need not be constant allthe way around the needle or in the whole length of the first area. Theactual thickness or thickness distribution will depend on the choice ofmaterial and the dimensions e.g. length and diameter of the first area.Also the distance between the connector needle 19 and the membrane 17will be of importance when determining how the membrane will be deformedwhen subjected to a pressure from the closed end i.e. if the distancebetween the outer surface of the connector needle 19 and the inner wallof the membrane is very small the walls of the membrane will when theyare pushed back be guided by the contact with the connector needle 19and not by the thickness i.e. the rigidity of the membrane material.

The second area comprises a portion of the membrane 17 which ispositioned between the first and the third area. At least a part of thematerial of the membrane 17 in the second area has the thickness b₁, andthe second area may have the form of one or more hollow truncatedcone(s) or a cylinder(s) forming thick and thin parts in the membranematerial in order to form folding features which define exactly wherethe membrane material will deform and how the material will deform.Normally the folding features are shaped to make the membrane materialdeform outward but as the rigid walls of the needle 19 assures that thefluid can keep flowing inside the needle 19, the membrane might as welldeform inwards. Normally: b₂>b₁ and for some materials often used formembranes of this type: b₂1.5·b₁. If the distance between the connectorneedle 19 and the membrane 17 in the first area is very small i.e. below0.5 mm, the membrane thickness b2 might be smaller than b1 as themembrane can then wrinkle or fold when being pushed back along theconnector needle 19. In this case the connector needle 19 placed insidethe membrane 17 functions as a guide and a support for the membrane 17.

The third area comprises a part of the membrane material which is shapedin such a way that it can be used to fasten the membrane 17 to theholding part 61. The third area can comprise membrane material in athickness and flexibility which e.g. makes it adequate for fitting overand squeezing around a protruding part 61 a of the holding part 61provided e.g. around the needle 19, or it can e.g. be shaped with anoutward brim of material which makes it possible to squeeze the brimbetween two parts of the holding part 61.

FIG. 2A-C show an embodiment of a membrane according to the inventionused in a connection part 3 providing a fluid path to or from areservoir to a patient. The connection part 3 is attached to a surfaceplate 1 which surface plate 1 is attached to a contact surface 2. Thesurface plate 1 is in this embodiment constructed of a molded plasticmaterial and the contact surface is the proximal side of a mounting pad2 which mounting pad 2 is unreleasably fastened to the surface plate 1during manufacturing of the device.

The connection part 3 is attached to or integrated with the surfaceplate 1. According to the present embodiment the surface plate 1 and atleast an outer cover of the connection part 3 is simply molded in onepiece during manufacturing of the device. The connection part 3 forms afluid path between e.g. a reservoir of medication, nutrients or the liketo be supplied to a patient or a reservoir for liquid collected from apatient e.g. via a cannula part 7. Therefore the connection part 3 isprovided with at least two openings, one opening at each end of thefluid path where the first opening 13 is an inlet or outlet openingreceiving or delivering fluid to a reservoir 6 and the second opening 12is an inlet or outlet opening receiving or delivering fluid to a cannulapart 7. The connection part 3 might be provided with extra openings e.g.for injection of a second medication or nutrient or for letting thefluid in the fluid path get in contact with a sensor. FIG. 1 shows thereservoir 6 attached to the connection part 3 at the first opening 13 ofthe connection part 3. In the following the first opening 13 will bereferred to as “inlet” and the second opening 12 will be referred to as“outlet” although the direction of the flow through the fluid path isnot significant for the invention.

The connection part 3 is further provided with a cannula opening 12Awhich accurately fits around a cannula part 7 when the cannula part 7 ismounted in the connection part 3 i.e. the cannula opening 12A has thesame shape or profile as the cannula part 7 and is just big enough tolet the cannula part 7 pass through and then fit into the opening. InFIG. 2A the cannula part 7 is shown in a position where the cannula part7 is not fully inserted, normally the cannula part 7 would at this stageof insertion still be placed inside an inserter and it would not bevisible. When the cannula part 7 is fully inserted, the upper surfacei.e. the distal surface of the cannula part 7 is normally at level withor at a lower level than the outer surface of the connection part 3around the cannula opening 12A. An enlargement of a cannula part 7 whichcan be used with the connection part 3 is shown in FIGS. 2D and 2E.

When the cannula part 7 has been fully inserted into the connection part3, an opening 20 in a flat side surface 25 of the body 24 of the cannulapart 7 corresponds to the opening 12 of the fluid path of the connectionpart 3 and fluid can flow from one part to the other. The opening 20 inthe body 24 of the cannula part 7 might in the following be referred toas an “inlet” although the direction of the flow is not significant tothe invention. The cannula part 7 is provided with a top opening 21which allows access to the cannula part 7 by the use of a needle andwith attachment means 23 in the form of an upward surface which fitsunder a not shown flexible part of the base part, and when the cannulapart 7 is correctly positioned in the base part, it will be locked tothe position and it will not be possible to remove the cannula part 7again.

FIG. 2A show the embodiment of the connection part 3 in an exploded viewwhere the internal holding parts 61 for a tube 60 providing a fluid pathis shown. FIG. 2B shows a cut through the internal holding part 61according to which it is possible to see the position of the tube 60.FIG. 2C shows an enlargement of the encircled part of FIG. 2A.

According to the present embodiment the connection part 3 and thesurface plate 1 is molded in one piece of a plastic material, theconnection part 3 is provided with several openings, one opening 12A isprepared for fitting in the cannula part 7 and another opening isprepared for fitting in the internal parts of the connection part 3. Theinternal parts of the connection part 3 according to this embodimentcomprises one tube which at two positions are bend in 90° i.e. both theinlet and the outlet end of the tube 60 points in the same directionperpendicular to the connecting part of the tube 60 where the connectingpart of the tube 60 forms the fluid path between the two bending parts.

At one end the tube 60 is protected by the bubble shaped membrane 17 andat the other end the tube 60 is open and unprotected. The open tube endis surrounded by a sealing 18 which sealing is attached unreleasably tothe holding part 61. When the internal parts has been placed in thecorresponding opening in the connection part 3 a cover 62 accuratelyfitting in the opening is placed in level with the surface of theconnection part 3 in such a way that the user experience a smoothsurface which cannot be tampered with.

FIG. 2B shows an enlargement of the internal parts of the connectionpart 3. The holding parts 61 comprise a single molded part which isproviding a stable embedment of the tube 60. The open end of the tube 60opens into a volume surrounded by the sealing 18. The closed end of thetube 60 opens into a volume which volume is completely surrounded by anelastic membrane 17. “Completely surrounded” means that there is no freeaccess to the surroundings, “elastic membrane” means that the membranecan be deformed and return to the original form and that the membranecan be penetrated by a needle, especially the connector needle 19 whichis provided by the end of the tube 60 and is adapted to penetrate themembrane 17. The membrane 17 is fastened to the holding part 61 as theelastic material at the open end 17 b of the membrane 17 squeezes aroundthe protruding part 61 a of the holding part 61. The end of the tube 60which constitutes the connector needle 19 is in this embodiment not intouch with the surrounding membrane 17 when the membrane is notsubjected to a pressure from the outside. The connector needle 19 issurrounded by air, and the internal space surrounding the connectorneedle 19 has a several zones of cylindrical or conical shape i.e. acircular cross-section. The first zone closest to the holding part hasapproximately both inner and outer cylindrical having walls ofapproximately constant thickness. The second or middle zone has innerand outer walls formed as truncated cones and the variations of theinner and outer walls result in that the walls have a decreasingthickness towards the holding part 61. The third zone which can also bereferred to as a passage 17 a is closest to and surrounding the tip ofthe connector needle 19, both the inner walls and the outer walls ofthis zone are slightly cone-shaped but could as well be cylindrical orhave an angular cross-section, the walls in this zone is thick althoughhaving slightly decreasing thickness towards the middle zone, the end ofthe zone is closed with a flat layer of membrane. When the a pressure isput on the flat end layer, the walls of the first zone of the membrane17 will deform by bending inwards or outwards when the length of themembrane 17 is reduced as a result of the applied pressure. As themembrane 17 is placed behind the opening 13 when liquid is transferrede.g. from a reservoir to the connector needle 19, fluid will not bepresent in the volume surrounding the connector needle 19. When thepressure is removed and the membrane 17 returns to the position in frontof the opening 13, fluid will normally not run out of the connectorneedle 19 as the connector needle 19 has a relatively small diameter (<1mm) and there is no free access of air at the cannula end of the tube60.

FIG. 2C shows an enlargement of the enclosed field marked in FIG. 2A.

FIG. 3A shows another embodiment of a bubble shaped membrane 17.According to this embodiment the reservoir 6 which is provided with anentrance protecting membrane 6A is pushed toward the bubble membrane 17covering the connector needle 19. The bubble membrane 17 is made of aflexible material which makes it possible for the membrane to bedeformed to such an extent that the connector needle 19 can penetratethe protecting membrane 6A and extend into the reservoir therebyproviding access to the fluid reservoir 6.

FIG. 3B shows another embodiment where a bubble membrane 6A is mountedat the outlet of a reservoir 6 which outlet can be connected to thefluid path of the connection path 3. The not shown end of the fluid pathconnecting to the reservoir 6 is provided with a membrane protecting theentrance of the fluid path during periods where the fluid path is notconnected to the reservoir 6. According to this embodiment the fluidpath need not be provided with a connector needle 19 as the connectorneedle 19 is part of the reservoir 6.

FIG. 3C shows yet another embodiment of a bubble membrane 17 and how thereservoir is pressed against the connector needle 19 in order to providea fluid path for the medication contained in the reservoir 6. The bubblemembrane 17 is flexible and is able to be reduced in size in such a waythat it allows the entrance of the reservoir 6 to be pressed into theopening in the connection part 3 which surrounds the membrane 17 and theconnector needle 19 i.e. the length of the membrane 17 can be reducedwithout the diameter of the membrane 17 being extended. According to theshown embodiment the material of the membrane will be folded inwards.

FIGS. 4A-C show a device according to the invention comprising a basepart comprising a fluid path provided with a membrane 17 and a deliverypart comprising a reservoir 6, the two parts are in a position wherethey are separated from each other and they are shown from differentangles. In FIG. 4A the two parts are seen from below. This view shows anopening 12B through which the penetrating member 7 can be insertedthrough the base part and through which opening 12B the cannula 22extends. From this view it is possible to see how the reservoir 6 can bepositioned in the delivery part 8 and to see how two opposite positionedrelease handles 9 are placed at the edge of the delivery part 8. Furthera longitudinal track corresponding to longitudinal raised guiding means4 on the base part can be seen.

The two release handles 9 are formed as s-shaped bands where one end isfastened hinge-like to the housing of the delivery part 8 and the firstcurve in the s-shape is slightly extending the outer surface of thehousing of the delivery part whereas the second curve is free i.e. notattached to the housing of the delivery part 8 and is provided with ahook-like shape which can fold around a part 15 protruding from thedistal surface of the base part. When the delivery part is locked to thebase part both release handles 9 are folded round a protruding part 15,when the delivery part 8 is to be removed from the base part, the twoopposite release handles 9 are pushed together whereby the hook-likeparts of the release handles 9 are released from the protruding parts 15of the base part, and the delivery part can be moved backwards i.e. inthe direction away from the cannula part 7 and removed from the basepart in this direction.

In FIG. 4B the two parts are shown from above. This view shows how thedelivery part 8 of this embodiment can be joined to the base part bypushing the delivery part 8 down toward the guiding means 4 which inthis case is a longitudinal raised platform having e.g. a metal lining 5fastened to the top surface. The delivery part 8 is provided withcorresponding means e.g. comprising a track corresponding to the raisedplatform 4. The corresponding means of the delivery part 8 can slidealong the metal lining 5 of the raised platform 4 of the base part inthe longitudinal direction. When the delivery part 8 arrives at itsworking position, the two release handles 9 engage respectively with thetwo protruding parts 15 protruding from the upper surface of the surfaceplate 1. When the delivery part 8 is in its working position it islocked in any horizontal direction by the release handles 9. The lockingmechanisms make it possible to fasten and release the delivery devicefrom the base part as often as needed i.e. a single-use base part can becombined with a multi-use delivery part.

In FIG. 4C the two parts are shown from the end opposite of where theinserter was fastened before insertion of the penetrating member. Fromthis side it is possible to see the inlet opening 13 in the connectionpart 3 through which e.g. medication from the reservoir 6 can enter, theinlet opening 13 is protected with a membrane to prevent contaminationwith microorganisms. According to one embodiment the connection part 3is provided with both a connector needle (not shown as it is placedbehind the bubble shaped membrane) and a bubble shaped self closingmembrane 17 and the reservoir 6 can be provided with a bubble shapedself closing membrane. Hereby a fluid path is established providingtransfer of medication e.g. insulin or nutrients from the reservoir tothe connector part 3. As both parts are provided with self closingmembranes it will be possible to separate the two units from each otherand rejoin them at a later time without the connection part 3 andthereby the patient being contaminated.

FIG. 5 shows an enlargement of a second embodiment of a membrane 17according to the invention. This bubble membrane 17 also completelysurrounds the part of the connector needle 19 which protrudes from thesurface of the not shown holding part 61 in which the connector needle19 is embedded. According to this embodiment the connector needle 19 ispositioned so close to the membrane 17 that it might touch the bubblemembrane 17 even when no pressure is put on the membrane 17 i.e. thepassage 17 a between the needle 19 and the membrane 17 represents adistance between membrane 17 and needle 19 close to 0, normally thedistance will be less than 0.5 mm. When the membrane 17 is positionedthis close to the connector needle 19, the needle 19 functions asguiding means when pressure is put on the membrane 17 which means thatit will be easier to predict the folding of the membrane.

The needle 19 does not pierce the membrane 17 when no pressure is put onthe membrane, this ensures filling of the membrane 17 with sterilizinggas such as Eto and distribution of the gas. The flexible membrane 17should include a small vent e.g. a small cut in the side of the membrane17 e.g. in the second area which cut opens when the membrane 17 ispushed over the needle 19. The vent allows for pressure relief.

1. A membrane (17) completely covering an opening (13) giving access toa space in a device which membrane (17) is made of an elastic materialpenetrable by a needle, the membrane (17) is fastened around the opening(13) and the membrane (17) protrudes from the opening (13) and forms anair filled volume in front of the opening (13) which air filled volumecan be reduced in size when a pressure is put on the membrane (17) fromthe outside, the inner surfaces of the membrane (17) define a passage(17 a) at the first closed end of the membrane (17) through which aneedle (19) can pass and the second end of the membrane (17) is adaptedto attach the membrane (17) to a holding part (61), characterized inthat the walls of the membrane (17) have a thickness and shape of thechosen membrane material making it possible, to maintain the protrudingshape in a use position without the outer surfaces of the membrane (17)being supported with walls of rigid material.
 2. A membrane according toclaim 1, wherein the second end of the membrane (17) has an internalopening (17 b) fitting around the outer contour of a protruding part (61a) on the holding part (61) and that the membrane (17) is fastened tothe holding part (61) by interference fit.
 3. A membrane according toclaim 1 or 2, wherein the membrane (17) is supported with walls of arigid material on the inner surfaces of the membrane (17) e.g. in theform of a penetrating needle.
 4. A membrane according to claim 1, 2 or3, wherein the cross-section of the air-filled volume in the passage (17a) is smaller than 2·[max cross-section of the opening (13)].
 5. Amembrane according to any preceding claim, wherein the membrane (17) hasa constant or decreasing outer cross-section from where the membrane(17) is attached to the device and to the proximal end, and the passage(17 a) is formed by increasing the thickness of the walls of themembrane (17) at the proximal end of the membrane (17) thereby reducingthe inner air-filled cross-section of the membrane (17).
 6. A membraneaccording to any preceding claim, wherein the properties of the materialforming the membrane (17) forming folding sections and making itpossible to predict how the air filled volume is reduced when subjectedto an external pressure.
 7. A membrane according to any of the precedingclaims, wherein the membrane (17) can be penetrated by a pointy needle.8. A membrane according to any of the preceding claim, wherein thematerial of the membrane (17) positioned closest to the device has thethickness b₁ and has the form of a hollow truncated cone or a cylinderand the material positioned furthest away from the device has athickness b₂ and has the form of a hollow cylinder which is closed atthe end opposite the device, and b₂>b₁.
 9. A membrane according to claim8, wherein a part of the membrane (17) positioned between the materialclosest to the device having the thickness b₁ and the materialpositioned furthest away from the device having a thickness b₂, has athickness varying from b₁ to b₂.
 10. A membrane according to claim 8 or9, wherein b₂≧1.5·b₁.
 11. A membrane according to any of the claims 3-7,wherein b₂<b₁ and the distance between the rigid material supporting theinner surfaces of the membrane (17) and the inner surfaces of themembrane (17) is less than 0.5 mm.
 12. A device comprising a membrane(17) according to any of the claims 1-11, a base part which base partcomprise a surface plate (1), fastening means which fasten the base partto a subject, a fluid path (3) having at least two openings (12, 13): aninlet and an outlet for fluid, where one opening (13) is protected bythe membrane (17) and the second opening during use connects to apenetrating part (7) transferring fluid to and/or from the subject inwhich it is inserted.
 13. A device according to claim 12, wherein theopening (13) is provided at the end of a needle (19) which needle (19)is fastened unreleasably to the device and the needle (19) is placed inthe air filled volume inside the membrane (17) and during periods whereno pressure is put on the membrane (17) the part of the needle (19)extending into the air filled volume is completely surrounded by air.14. A device according to claim 13, wherein the needle (19) duringperiods where pressure is put on the membrane (17) extends through themembrane (17) and protrudes from the outer surface of the membrane (17).15. A device according to claim 12, 13 or 14, wherein the needle (19) isa pointy needle.
 16. A device according to claim 12, 13, 14 or 15,wherein the penetrating part (7) comprises a cannula (22).
 17. A kitcomprising a device comprising a membrane according to any of the claims1-11 and a unit adapted to be joined to the device assuring a steriletransfer of fluid between the device and the joined unit.